CHAPTER III
The Onlooker's Philosophic Malady
In his isolation as world spectator, the modern philosopher was bound to reach two completely opposite views regarding the objective value of human thought. One of these was given expression in Descartes' famous words:Cogito ergo sum('I think, therefore I am'). Descartes (1596-1650), rightly described as the inaugurator of modern philosophy, thus held the view that only in his own thought-activity does man find a guarantee of his own existence.
In coming to this view, Descartes took as his starting-point his experience that human consciousness contains only the thought pictures evoked by sense-perception, and yet knows nothing of the how and why of the things responsible for such impressions. He thus found himself compelled, in the first place, to doubt whether any of these things had any objective existence, at all. Hence, there remained over for him only one indubitable item in the entire content of the universe - his own thinking; for were he to doubt even this, he could do so only by again making use of it. From the 'I doubt, therefore I am', he was led in this way to the 'I think, therefore I am'.
The other conception of human thought reached by the onlooker-consciousness was diametrically opposed to that of Descartes, and entirely cancelled its conceptual significance. It was put forward - not long afterwards - by Robert Hooke (1635-1703), the first scientist to make systematic use of the newly invented microscope by means of which he made the fundamental discovery of the cellular structure of plant tissues. It was, indeed, on the strength of his microscopic studies that he boldly undertook to determine the relationship of human thought to objective reality. He published his views in the introduction to hisMicrographia,the great work in which, with the lavish help of carefully executed copper engravings, he made his microscopic observations known to the world.
Hooke's line of thought is briefly as follows: In past ages men subscribed to the naive belief that what they have in their consciousness as thought pictures of the world, actually reproduces the real content of that world. The microscope now demonstrates, however, how much the familiar appearance of the world depends on the structure of our sense apparatus; for it reveals a realm just as real as that already known to us, but hitherto concealed from us because it is not accessible to the natural senses. Accordingly, if the microscope can penetrate through the veil of illusion which normally hides a whole world of potentially visible phenomena, it may be that it can even teach us something about the ideas we have hitherto formed concerning the nature of things. Perhaps it can bring us a step nearer the truth in the sphere of thought, as it so obviously has done in that of observation.
Of all the ideas that human reason can form, Hooke considered the simplest and the most fundamental to be the geometrical concepts of point and straight line. Undoubtedly we are able to think these, but the naïve consciousness takes for granted that it also perceives them as objective realities outside itself, so that thoughts and facts correspond to each other. We must now ask, however, if this belief is not due to an optical deception. Let us turn to the microscope and see what point and line in the external world look like through it.
For his investigation Hooke chose the point of a needle and a knife-edge, as providing the best representatives among physical objects of point and straight line. In the sketches here reproduced we may see how Hooke made clear to his readers how little these two things, when observed through the microscope, resemble what is seen by the unaided eye. This fact convinced Hooke that the apparent agreement between the world of perception and the world of ideas rests on nothing more solid than an optical limitation (Plate I).
Compared with the more refined methods of present-day thought, Hooke's procedure may strike us as somewhat primitive. Actually he did nothing more than has since been done times without number; for the scientist has become more and more willing to allow artificially evoked sense-perceptions to dictate the thoughts he uses in forming a scientific picture of the world.
In the present context we are concerned with the historical import of Hooke's procedure. This lies in the fact that, immediately after Descartes had satisfied himself that in thinking man had the one sure guarantee of his own existence, Hooke proved in a seemingly indubitable manner that thinking was entirely divorced from reality. It required only another century for philosophy to draw from this the unavoidable consequence. It appeared in the form of Hume's philosophic system, the outcome of which was universal scepticism.
As we shall see in due course, Hume's mode of reasoning continues to rule scientific thought even to-day, quite irrespective of the fact that science itself claims to have its philosophical parent in Kant, the very thinker who devoted his life's work to the refutation of Hume.
*
On the basis of his investigations into human consciousness Hume felt obliged to reason thus: My consciousness, as I know it, has no contact with the external world other than that of a mere outside onlooker. What it wins for its own content from the outer world is in the nature of single, mutually unrelated parts. Whatever may unite these parts into an objective whole within the world itself can never enter my consciousness; and any such unifying factor entertained by my thought can be only a self-constructed, hypothetical picture. Hume summed up his view in two axioms which he himself described as the alpha and omega of his whole philosophy. The first runs: 'All our distinct perceptions are distinct existences.' The other: 'The Mind never perceives any real connexions between distinct existences.'(Treatise of Human Nature.)
If once we agree that we can know of nothing but unrelated thought pictures, because our consciousness is not in a position to relate these pictures to a unifying reality, then we have no right to ascribe, with Descartes and his school, an objective reality to the self. Even though the self may appear to us as the unifying agent among our thoughts, it must itself be a mental picture among mental pictures ; and man can have no knowledge of any permanent reality outside this fluctuating picture-realm. So, with Hume, the onlooker-consciousness came to experience its own utter inability to achieve a knowledge of the objective existence either of a material world be - behind all external phenomena, or of a spiritual self behind all the details of its own internal content.
Accordingly, human consciousness found itself hurled into the abyss of universal scepticism. Hume himself suffered unspeakably under the impact of what he considered inescapable ideas - rightly described from another side as the 'suicide of human intelligence' - and his philosophy often seemed to him like a malady, as he himself called it, against whose grip he could see no remedy. The only thing left to him, if he was to prevent philosophical suicide from ending in physical suicide, was to forget in daily life his own conclusions as far as possible.
What Hume experienced as his philosophical malady, however, was the result not of a mental abnormality peculiar to himself, but of that modern form of consciousness which still prevails in general today. This explains why, despite all attempts to disprove Hume's philosophy, scientific thought has not broken away from its alpha and omega in the slightest degree.
A proof of this is to be found, for example, in the principle of Indeterminacy which has arisen in modern physics.
*
The conception of Indeterminacy as an unavoidable consequence of the latest phase of physical research is due to Professor W. Heisenberg. Originally this conception forced itself upon Heisenberg as a result of experimental research. In the meantime the same idea has received its purely philosophical foundation. We shall here deal with both lines of approach.
After the discovery by Galileo of the parallelogram of forces, it became the object of classical physics - unexpressed, indeed, until Newton wrote hisPrincipia- to bring the unchanging laws ruling nature into the light of human consciousness, and to give them conceptual expression in the language of mathematical formulae. Since, however, science was obliged to restrict itself to what could be observed with a single, colour-blind eye, physics has taken as its main object of research the spatio-temporal relationships, and their changes, between discrete, ideally conceived, point-like particles. Accordingly, the mathematically formulable laws holding sway in nature came to mean the laws according to which the smallest particles in the material foundation of the world change their position with regard to each other. A science of this kind could logically maintain that, if ever it succeeded in defining both the position and the state of motion, in one single moment, of the totality of particles composing the universe, it would have discovered the law on which universal existence depends. This necessarily rested on the presupposition that it really was the ultimate particles of the physical world which were under observation. In the search for these, guided chiefly by the study of electricity, the physicists tracked down ever smaller and smaller units; and along this path scientific research has arrived at the following peculiar situation.
To observe any object in the sense world we need an appropriate medium of observation. For ordinary things, light provides this. In the sense in which light is understood to-day, this is possible because the spatial extension of the single light impulses, their so-called wavelength, is immeasurably smaller than the average magnitude of all microscopically visible objects. This ensures that they can be observed clearly by the human eye. Much smaller objects, however, will require a correspondingly shorter wave-length in the medium of observation. Now shorter wave-lengths than those of visible light have been found in ultra-violet light and in X-rays; and these, accordingly, are now often used for minute physical research.
In this way, however, we are led by nature to a definite boundary; for we now find ourselves in a realm where the dimensions of the observation medium and the observed object are more or less the same. The result, unfortunately, is that when the 'light' meets the object, it changes the latter's condition of movement. On the other hand, if a 'light' is used whose wave-length is too big to have any influence on the object's condition of movement, it precludes any exact determination of the object's location.
Thus, having arrived at the very ground of the world - that is, where the cosmic laws might be expected to reveal themselves directly - the scientist finds himself in the remarkable situation of only being able to determine accurately either the position of an observed object and not its state of motion, or its state of motion and not its position. The law he seeks, however, requires that both should be known at the same time. Nor is this situation due to the imperfection of the scientific apparatus employed, but to its very perfection, so that it appears to arise from the nature of the foundation of the world - in so far, at least, as modern science is bound to conceive it.
If it is true that a valid scientific knowledge of nature is possible only in the sphere open to a single-eyed, colour-blind observation, and if it is true - as a science of this kind, at any rate, is obliged to believe - that all processes within the material foundation of the world depend on nothing but the movements of certain elementary particles of extremely small size, then the fact must be faced that the very nature of these processes rules out the discovery of any stable ordering of things in the sense of mathematically formulable laws. The discovery of such laws will then always be the last step but one in scientific investigation; the last will inevitably be the dissolution of such laws into chaos. For a consistent scientific thinking that goes this way, therefore, nothing is left but to recognize chaos as the only real basis of an apparently ordered world, a chaos on whose surface the laws that seem to hold sway are only the illusory picturings of the human mind. This, then, is the principle of Indeterminacy as it has been encountered in the course of practical investigation into the electrical processes within physical matter.
In the following way Professor Schrödinger, another leading thinker among modern theoretical physicists, explains the philosophical basis for the principle of Indeterminacy, which scientists have established in the meantime:1
'Every quantitative observation, every observation making use of measurement, is by nature discontinuous. ... However far we go in the pursuit of accuracy we shall never get anything other than a finite series of discrete results. ... The raw material of our quantitative cognition of nature will always have this primitive and discontinuous character. ... It is possible that a physical system might be so simple that this meagre information would suffice to settle its fate; in that case nature would not be more complicated than a game of chess. To determine a position of a game of chess thirty-three facts suffice. ... If nature is more complicated than a game of chess, a belief to which one tends to incline, then a physical system cannot be determined by a finite number of observations. But in practice a finite number of observations is all that we could make.'
Classical physics, the author goes on to show, held that it was possible to gain a real insight into the laws of the universe, because in principle an infinite number of such discrete observations would enable us to fill in the gaps sufficiently to allow us to determine the system of the physical world. Against this assumption modern physics must hold the view that an infinite number of observations cannot in any case be carried out in practice, and that nothing compels us to assume that even this would suffice to furnish us with the means for a complete determination, which alone would allow us to speak of 'law' in nature. 'This is the direction in which modern physics has led us without really intending it.'
What we have previously said will make it clear enough that in these words of a modern physicist we meet once more the two fundamentals of Hume's philosophy. It is just as obvious, however, that the very principle thus re-affirmed at the latest stage of modern physical science was already firmly established by Hooke, when he sought to prove to his contemporaries the unreality of human ideas.
Let us recall Hooke's motives and results. The human reason discovers that certain law-abiding forms of thought dwell within itself; these are the rules of mathematical thinking. The eye informs the reason that the same kind of law and order is present also in the outer world. The mind can think point and line; the eye reports that the same forms exist in nature outside. (Hooke could just as well have taken as his examples the apex and edge of a crystal.) The reason mistrusts the eye, however, and with the help of the microscope 'improves' on it. What hitherto had been taken for a compact, regulated whole now collapses into a heap of unordered parts; behind the illusion of law a finer observation detects the reality of chaos!
Had science in its vehement career from discovery to discovery not forgotten its own beginnings so completely, it would not have needed its latest researches to bring out a principle which it had in fact been following from the outset - a principle which philosophy had already recognized, if not in quite the same formulation, in the eighteenth century. Indeterminacy, as we have just seen it explained by Schrödinger, is nothing but the exact continuation of Humean scepticism.
1In his book,Science and the Human Temperament(Dublin, 1935).
CHAPTER IV
The Country that is Not Ours
The last two chapters have served to show the impasse into which human perception and thinking have come - in so far as they have been used for scientific purposes - by virtue of the relationship to the world in which man's consciousness found itself when it awoke to itself at the beginning of modern times. Now although the onlooker in man, especially in the earliest stage of our period, gave itself up to the conviction that a self-contained picture of the universe could be formed out of the kind of materials available to it, it nevertheless had a dim inkling that this picture, because it lacked all dynamic content, had no bearing on the real nature of the universe. Unable to find this reality within himself, the world-onlooker set about searching in his own way for what was missing, and turned to the perceptible world outside man. Here he came, all unexpectedly, upon ... electricity. Scarcely was electricity discovered than it drew human scientific thinking irresistibly into its own realm. Thereby man found himself, with a consciousness completely blind to dynamics, within a sphere of only too real dynamic forces. The following description will show what results this has had for man and his civilization.
*
First, let us recall how potent a role electricity has come to play in social life through the great discoveries which began at the end of the eighteenth century. To do this we need only compare the present relationship between production and consumption in the economic sphere with what it was before the power-machine, and especially the electrically driven machine, had been invented. Consider some major public undertaking in former times - say the construction of a great mediaeval cathedral. Almost all the work was done by human beings, with some help, of course, from domesticated animals. Under these circumstances the entire source of productive power lay in the will-energies of living beings, whose bodies had to be supplied with food, clothing and housing; and to provide these, other productive powers of a similar kind were required near the same place. Accordingly, since each of the power units employed in the work was simultaneously both producer and consumer, a certain natural limit was placed on the accumulation of productive forces in any one locality.
This condition of natural balance between production and consumption was profoundly disturbed by the introduction of the steam engine; but even so there were still some limits, though of a quite different kind, to local concentrations of productive power. For steam engines require water and coal at the scene of action, and these take up space and need continual shifting and replenishing. Owing to the very nature of physical matter, it cannot be heaped up where it is required in unlimited quantities.
All this changed directly man succeeded in producing energy electro-magnetically by the mere rotation of material masses, and in using the water-power of the earth - itself ultimately derived from the cosmic energies of the sun - for driving his dynamos. Not only is the source of energy thus tapped practically inexhaustible, but the machines produce it without consuming on their own account, apart from wear and tear, and so make possible the almost limitless accumulation of power in one place. For electricity is distinguished from all other power-supplying natural forces, living or otherwise, precisely in this, that it can be concentrated spatially with the aid of a physical carrier whose material bulk is insignificant compared with the energy supplied.
Through this property of electricity it has been possible for man to extend the range of his activity in all directions, far and near. So the balance between production and consumption, which in previous ages was more or less adequately maintained by natural conditions, has been entirely destroyed, and a major social-economic problem created.
In yet another way, and through quite another of its properties, electricity plays an important part in modern life. Not only does it compete with the human will; it also makes possible automatically intelligent operations quite beyond anything man can do on his own. There are innumerable examples of this in modern electrical technology; we need mention here only the photo-electric cell and the many devices into which it enters.
To an ever-increasing, quite uncontrolled degree - for to the mind of present-day man it is only natural to translate every new discovery into practice as soon and as extensively as possible - electricity enters decisively into our modern existence. If we take all its activities into account, we see arising amongst humanity a vast realm of labour units, possessed in their own way not only of will but of the sharpest imaginable intelligence. Although they are wholly remote from man's own nature, he more and more subdues his thoughts and actions to theirs, allowing them to take rank as guides and shapers of his civilization.
Turning to the sphere of scientific research, we find electricity playing a role in the development of modern thinking remarkably similar to its part as a labour-force in everyday life. We find it associated with phenomena which, in Professor Heisenberg's words, expose their mutual connexions to exact mathematical thinking more readily than do any other facts of nature; and yet the way in which these phenomena have become known has played fast and loose with mathematical thinking to an unparalleled degree. To recognize that in this sphere modern science owes its triumphs to a strange and often paradoxical mixture of outer accident and error in human thought, we need only review the history of the subject without prejudice.
*
The discovery of electricity has so far been accomplished in four clearly distinct stages. The first extends from the time when men first knew of electrical phenomena to the beginning of the natural scientific age; the second includes the seventeenth and the greater part of the eighteenth centuries; the third begins with Galvani's discovery and closes with the first observations of radiant electricity; and the fourth brings us to our own day. We shall here concern ourselves with a few outstanding features of each phase, enough to characterize the strange path along which man has been led by the discovery of electricity.
Until the beginning of modern times, nothing more was known about electricity, or of its sister force, magnetism, than what we find in Pliny's writings. There, without recognizing a qualitative distinction between them, he refers to the faculty of rubbed amber and of certain pieces of iron to attract other small pieces of matter. It required the awakening of that overruling interest in material nature, characteristic of our own age, for the essential difference between electric and magnetic attraction to be recognized. The first to give a proper description of this was Queen Elizabeth's doctor, Gilbert. His discovery was soon followed by the construction of the first electrical machine by the German Guericke (also known through his invention of the air pump) which opened the way for the discovery that electricity could be transmitted from one place to another.
It was not, however, until the beginning of the eighteenth century that the crop of electrical discoveries began to increase considerably: among these was the recognition of the dual nature of electricity, by the Frenchman, Dufais, and the chance invention of the Leyden jar (made simultaneously by the German, von Kleist, and two Dutchmen, Musschenbroek and Cunaeus). The Leyden jar brought electrical effects of quite unexpected intensity within reach. Stimulated by what could be done with electricity in this form, more and more people now busied themselves in experimenting with so fascinating a force of nature, until in the second third of the century a whole army of observers was at work, whether by way of profession or of hobby, finding out ever new manifestations of its powers.
The mood that prevailed in those days among men engaged in electrical research is well reflected in a letter written by the Englishman, Walsh, after he had established the electric nature of the shocks given by certain fishes, to Benjamin Franklin, who shortly before had discovered the natural occurrence of electricity in the atmosphere:
'I rejoice in addressing these communications to You. He, who predicted and shewed that electricity wings the formidable bolt of the Atmosphere, will hear with attention that in the deep it speeds a humbler bolt, silent and invisible; He, who analysed the electrical Phial, will hear with pleasure that its laws prevail in animate Phials; He, who by Reason became an electrician, will hear with reverence of an instinctive electrician, gifted in his birth with a wonderful apparatus, and with the skill to use it.' (Phil. Trans. 1773.)
Dare one believe that in electricity the soul of nature had been discovered? This was the question which at that time stirred the hearts of very many in Europe. Doctors had already sought to arouse new vitality in their patients by the use of strong electric shocks; attempts had even been made to bring the dead back to life by such means. . In a time like ours, when we are primarily concerned with the practical application of scientific discoveries, we are mostly accustomed to regard such flights of thought from a past age as nothing but the unessential accompaniment of youthful, immature science, and to smile at them accordingly as historical curiosities. This is a mistake, for we then overlook how within them was hidden an inkling of the truth, however wrongly conceived at the time, and we ignore the role which such apparently fantastic hopes have played in connexion with the entry of electricity into human civilization. (Nor are such hopes confined to the eighteenth century; as we shall see, the same impulse urged Crookes a hundred years later to that decisive discovery which was to usher in the latest phase in the history of science, a phase in which the investigating human spirit has been led to that boundary of the physical-material world where the transition takes place from inert matter into freely working energy.)
If there was any doubt left as to whether in nature the same power was at work which, in animal and man, was hidden away within the soul, this doubt seemed finally to have been dispelled through Galvani's discovery that animal limbs could be made to move electrically through being touched by two bits of different metals. No wonder that 'the storm which was loosed in the world of the physicists, the physiologists and the doctors through Galvani's publication can only be compared with the one crossing the political horizon of Europe at the same time. Wherever there happened to be frogs and two pieces of different metals available, everyone sought proof with his own eyes that the severed limbs could be marvellously re-enlivened.'1
Like many of his contemporaries, Galvani was drawn by the fascinating behaviour of the new force of nature to carry on electrical experiments as a hobby alongside his professional work, anatomical research. For his experiments he used the room where his anatomical specimens were set out. So it happened that his electrical machine stood near some frogs' legs, prepared for dissection. By a further coincidence his assistant, while playing with the machine, released a few sparks just when some of the specimens were in such contact with the surface beneath them that they were bound to react to the sudden alteration of the electric field round the machine caused by its discharge. At each spark the frogs' legs twitched. What Galvani saw with his own eyes seemed to be no less than the union of two phenomena, one observed by Franklin in the heights of the atmosphere, the other by Walsh in the depths of the sea.
Galvani, as he himself describes, proceeded with immense enthusiasm to investigate systematically what accident had thus put into his hands.2He wanted first to see whether changes occurring naturally in the electrical condition of the atmosphere would call forth the same reaction in his specimens. For this purpose he fastened one end of an iron wire to a point high up outside his house; the lower end he connected with the nervous substance of a limb from one of his specimens, and to the foot of this he attached a second wire whose other end he submerged in a well. The specimen itself was either enclosed in a glass flask in order to insulate it, or simply left lying on a table near the well. And all this he did whenever a thunderstorm was threatening. As he himself reported: 'All took place as expected. Whenever the lightning flashed, all the muscles simultaneously came into repeated and violent twitchings, so that the movements of the muscles, like the flash of the lightning, always preceded the thunder, and thus, as it were, heralded its coming.' We can have some idea of what went on in Galvani's mind during these experiments if we picture vividly to ourselves the animal limbs twitching about every time the lightning flashed, as if a revitalizing force of will had suddenly taken possession of them.
In the course of his investigations - he carried them on for a long time - Galvani was astonished to observe that some of his specimens, which he had hung on to an iron railing by means of brass hooks, sometimes fell to twitching even when the sky was quite clear and there was no sign of thunder. His natural conclusion was that this must be due to hitherto unnoticed electrical changes in the atmosphere. Observations maintained for hours every day, however, led to no conclusive result; when twitchings did occur it was only with some of the specimens, and even then there was no discoverable cause. Then it happened one day that Galvani, 'tired out with fruitless watching', took hold of one of the brass hooks by which the specimens were hung, and pressed it more strongly than usual against the iron railing. Immediately a twitching took place. 'I was almost at the point of ascribing the occurrence to atmospheric electricity,' Galvani tells us. All the same he took one of the specimens, a frog, into his laboratory and there subjected it to similar conditions by putting it on an iron plate, and pressing against this with the hook that was stuck through its spinal cord. Immediately the twitching occurred again. He tried with other metals and, for checking purposes, with non-metals as well. With some ingenuity he fixed up an arrangement, rather like that of an electric bell, whereby the limbs in contracting broke contact and in relaxing restored it, and so he managed to keep the frog in continuous rhythmical movement.
Whereas Galvani had been rightly convinced by his earlier observations that the movement in the specimens represented a reaction to an electric stimulus from outside, he now changed his mind. In the very moment of his really significant discovery he succumbed to the error that he had to do with an effect of animal electricity located somewhere in the dead creature itself, perhaps in the fashion of what had been observed in the electric fishes. He decided that the metal attachment served merely to set in motion the electricity within the animal.
Whilst Galvani persisted in this mistake until his death, Volta realized that the source of the electric force, as in the first of Galvani's observations, must still be sought outside the specimens, and himself rightly attributed it to the contacting metals. Guided by this hypothesis, Volta started systematic research into the Galvanic properties of metals, and presently succeeded in producing electricity once more from purely mineral substances, namely from two different metals in contact with a conductive liquid.
This mode of producing electricity, however, differed from any previously known in allowing for the first time the production of continuous electrical effects. It is this quality of the cells and piles constructed by Volta that laid open the road for electric force to assume that role in human civilization which we have already described. That Volta himself was aware of this essentially new factor in the Galvanic production of electricity is shown by his own report to the Royal Society:
'The chief of my results, and which comprehends nearly all the others, is the construction of an apparatus which resembles in its effects, viz. such as giving shocks to the arms, &c, the Leyden phial, and still better electric batteries weakly charged; . . . but which infinitely surpasses the virtue and power of these same batteries; as it has no need, like them, of being charged beforehand, by means of a foreign electricity; and as it is capable of giving the usual commotion as often as ever it is properly touched.'
Whilst Volta's success was based on avoiding Galvani's error, his apparatus nevertheless turned out inadvertently to be a close counterpart of precisely that animal organ which Galvani had in mind when misinterpreting his own discoveries! That Volta himself realized this is clear from the concluding words in his letter:
'This apparatus, as it resembles more the natural organ of the torpedo, or of the electrical eel, than the Leyden Phial or the ordinary electric batteries, I may call an artificial electric organ.'
This new method of producing continuous electrical effects had far-reaching results, one of which was the discovery of the magnetic properties of the electric current by the Dane, Oersted - once again a purely accidental discovery, moving directly counter to the assumptions of the discoverer himself. About to leave the lecture room where he had just been trying to prove the non-existence of such magnetic properties (an attempt seemingly crowned with success), Oersted happened to glance once more at his demonstration bench. To his astonishment he noticed that one of his magnetic needles was out of alignment; evidently it was attracted by a magnetic field created by the current running through a wire he had just been using, which was still in circuit. Thus what had escaped Oersted throughout his planned researches - namely, that the magnetic force which accompanies an electric current must be sought in a direction at right angles to the current - a fortuitous event enabled him to detect.
These repeated strokes of chance and frequently mistaken interpretations of the phenomenon thus detected show that men were exploring the electrical realm as it were in the dark; it was a realm foreign to their ordinary ideas and they had not developed the forms of thought necessary for understanding it. (And this, as our further survey will show, is still true, even to-day.)
In our historical survey we come next to the researches of Faraday and Maxwell. Faraday was convinced that if electrical processes are accompanied by magnetic forces, as Oersted had shown, the reverse must also be true - magnetism must be accompanied by electricity. He was led to this correct conviction by his belief in the qualitative unity of all the forces of nature - a reflexion, as his biography shows, of his strongly monotheistic, Old Testament faith. Precisely this view, however - which since Faraday natural science has quite consciously adopted as a leading principle - will reveal itself to us as a fundamental error.
It seems paradoxical to assert that the more consistently human thought has followed this error, the greater have been the results of the scientific investigation of electricity. Precisely this paradox, however, is characteristic of the realm of nature to which electricity belongs; and anyone earnestly seeking to overcome the illusions of our age will have to face the fact that the immediate effectiveness of an idea in practice is no proof of its ultimate truth.
Another eloquent example of the strange destiny of human thought in connexion with electricity is to be found in the work of Clark Maxwell, who, starting from Faraday's discoveries, gave the theory of electricity its mathematical basis. Along his purely theoretical line of thought he was led to the recognition of the existence of a form of electrical activity hitherto undreamt of - electro-magnetic vibrations. Stimulated by Maxwell's mathematical conclusions, Hertz and Marconi were soon afterwards able to demonstrate those phenomena which have led on the one hand to the electro-magnetic theory of light, and on the other to the practical achievements of wireless communication.
Once again, there is the paradoxical fact that this outcome of Maxwell's labours contradicts the very foundation on which he had built his theoretical edifice. For his starting-point had been to form a picture of the electro-magnetic field of force to which he could apply certain well-known formulae of mechanics. This he did by comparing the behaviour of the electrical force to the currents of an elastic fluid - that is, of a material substance. It is true that both he and his successors rightly emphasized that such a picture was not in any way meant as an explanation of electricity, but merely as an auxiliary concept in the form of a purely external analogy. Nevertheless, it was in the guise of a material fluid that he thought of this force, and that he could submit it to mathematical calculation. Yet the fact is that from this starting-point the strict logic of mathematics led him to the discovery that electricity is capable of behaviour which makes it appear qualitatively similar to ... light!
Whilst practical men were turning the work of Faraday and Maxwell to account by exploiting the mechanical working of electricity in power-production, and its similarity to light in the wireless communication of thought, a new field of research, with entirely new practical possibilities, was suddenly opened up in the last third of the nineteenth century through the discovery of how electricity behaves in rarefied air. This brings us to the discovery of cathode rays and the phenomena accompanying them, from which the latest stage in the history of electricity originated. And here once more, as in the history of Galvani's discoveries, we encounter certain undercurrents of longing and expectation in the human soul which seemed to find an answer through this sudden, great advance in the knowledge of electricity - an advance which has again led to practical applications of the utmost significance for human society, though not at all in the way first hoped for.
Interest in the phenomena arising when electricity passes through gases with reduced pressure had simultaneously taken hold of several investigators in the seventies of the nineteenth century. But the decisive step in this sphere of research was taken by the English physicist, William Crookes. He was led on by a line of thought which seems entirely irrelevant; yet it was this which first directed his interest to the peculiar phenomena accompanying cathode rays; and they proved to be the starting-point of the long train of inquiry which has now culminated in the release of atomic energy.3
In the midst of his many interests and activities, Crookes was filled from his youth with a longing to find by empirical means the bridge leading from the world of physical effects to that of superphysical causes. He himself tells how this longing was awakened in him by the loss of a much-beloved brother. Before the dead body he came to the question, which thereafter was never to leave him, whether there was a land where the human individuality continues after it has laid aside its bodily sheath, and how that land was to be found. Seeing that scientific research was the instrument which modern man had forged to penetrate through the veil of external phenomena to the causes producing them, it was natural for Crookes to turn to it in seeking the way from the one world into the other.
It was after meeting with a man able to produce effects within the corporeal world by means of forces quite different from those familiar to science, that Crookes decided to devote himself to this scientific quest. Thus he first came into touch with that sphere of phenomena which is known as spiritualism, or perhaps more suitably, spiritism. Crookes now found himself before a special order of happenings which seemed to testify to a world other than that open to our senses; physical matter here showed itself capable of movement in defiance of gravity, manifestations of light and sound appeared without a physical source to produce them. Through becoming familiar with such things at seances arranged by his mediumistic acquaintance, he began to hope that he had found the way by which scientific research could overstep the limits of the physical world. Accordingly, he threw himself eagerly into the systematic investigation of his new experiences, and so became the father of modern scientific spiritism.
Crookes had hoped that the scientists of his day would be positively interested in his researches. But his first paper in this field, 'On Phenomena called Spiritual', was at once and almost unanimously rejected by his colleagues, and as long as he concerned himself with such matters he suffered through their opposition. It passed his understanding as a scientist why anything should be regarded in advance as outside the scope of scientific research. After several years of fruitless struggle he broke off his investigations into spiritism, deeply disillusioned at his failure to interest official science in it. His own partiality for it continued, however (he served as President of the Society for Psychical Research from 1896-9), and he missed no opportunity of confessing himself a pioneer in the search for the boundary-land between the worlds of matter and spirit. Through all his varied scientific work the longing persisted to know more of this land.
Just as Crookes had once sought to investigate spiritism scientifically, so in his subsequent scientific inquiries he was always something of a spiritist. He admitted, indeed, that he felt specially attracted by the strange light effects arising when electricity passes through rarefied gases, because they reminded him of certain luminous phenomena he had observed during his spiritistic investigations. Besides this, there was the fact that light here showed itself susceptible to the magnetic force in a way otherwise characteristic only of certain material substances. Accordingly, everything combined to suggest to Crookes that here, if anywhere, he was at the boundary between the physical and the superphysical worlds. No wonder that he threw himself into the study of these phenomena with enthusiasm.
He soon succeeded in evoking striking effects - light and heat, and also mechanical - along the path of electricity passing invisibly through the tube later named after him. Thus he proved for the first time visibly, so to say, the double nature - material and supermaterial - of electricity. What Crookes himself thought about these discoveries in the realm of the cathode rays we may judge from the title, 'Radiant Matter', or 'The Fourth State of Matter', which he gave to his first publication about them. And so he was only being consistent when, in his lectures before the Royal Institution in London, and the British Association in Sheffield in 1879, after showing to an amazed scientific audience the newly discovered properties of electricity, he came to the climax of his exposition by saying: 'We have seen that in some of its properties Radiant Matter is as material as this table, whilst in other properties it almost assumes the character of Radiant Energy. We have actually touched here the borderland where Matter and Force seem to merge into one another, the shadowy realm between Known and Unknown, which for me has always had peculiar temptations.' And in boldly prophetic words, which time has partly justified, he added, 'I venture to think that the greatest scientific problems of the future will find their solution in this Borderland, and even beyond; here, it seems to me, lie Ultimate Realities, subtle, far-reaching, wonderful.'
No one can read these words of Crookes without hearing again, as an undertone, the question which had forced itself on him at the bedside of his dead brother, long before. All that is left of the human being whom death has taken is a heap of substances, deserted by the force which had used them as the instrument of its own activity. Whither vanishes this force when it leaves the body, and is there any possibility of its revealing itself even without occupying such a body?
Stirred by this question, the young Crookes set out to find a world of forces which differ from the usual mechanical ones exercised by matter on matter, in that they are autonomous, superior to matter in its inert conglomeration, yet capable of using matter, just as the soul makes use of the body so long as it dwells within it. His aim was to secure proof that such forces exist, or, at any rate, to penetrate into the realm where the transition from matter to pure, matter-free force takes place. And once again, as in Galvani's day, electricity fascinated the eyes of a man who was seeking for the land of the soul. What spiritism denied, electricity seemed to grant.
The aversion to spiritism which Crookes met with in contemporary science was, from the standpoint of such a science, largely justified. Science, in the form in which Crookes himself conceived it, took for granted that the relationship of human consciousness to the world was that of external onlooking. Accordingly, if the scientist remained within the limits thus prescribed for consciousness, it was only consistent to refuse to make anything beyond these limits an object of scientific research.
On the other hand, it says much for the courage and open mindedness of Crookes that he refused to be held back from what was for him the only possible way of extending the boundaries of science beyond the given physical world. Moreover, it was only natural that in his search for a world of a higher order than the physical he should, as a man of his time, first turn his attention to spiritistic occurrences, for spiritism, as it had come over to Europe from America in the middle of the nineteenth century, was nothing but an attempt by the onlooker-consciousness to learn something in its own way about the supersensible world. The spiritist expects the spirit to reveal itself in outwardly perceptible phenomena as if it were part of the physical world. Towards the end of his life Crookes confessed that if he were able to begin again he would prefer to study telepathic phenomena - the direct transference of thought from one person to another - rather than the purely mechanical, or so-called telekinetic, expressions of psychic forces. But although his interest was thus turning towards a more interior field of psychic investigation, he remained true to his times in still assuming that knowledge about the world, whatever it might be, could be won only by placing oneself as a mere onlooker outside the object of research.
*
The stream of new discoveries which followed Crookes's work justified his conviction that in cathode ray phenomena we have to do with a frontier region of physical nature. Still, the land that lies on the other side of this frontier is not the one Crookes had been looking for throughout his life. For, instead of finding the way into the land whither man's soul disappears at death, Crookes had inadvertently crossed the border into another land - a land which the twentieth-century scientist is impelled to call 'the country that is not ours'.
The realm thrown open to science by Crookes's observations, which human knowledge now entered as if taking it by storm, was that of the radioactive processes of the mineral stratum of the earth. Many new and surprising properties of electricity were discovered there - yet the riddle of electricity itself, instead of coming nearer, withdrew into ever deeper obscurity.
The very first step into this newly discovered territory made the riddle still more bewildering. As we have said, Maxwell's use of a material analogy as a means of formulating mathematically the properties of electro-magnetic fields of force had led to results which brought electricity into close conjunction with light. In his own way Crookes focused, to begin with, his attention entirely on the light-like character of electric effects in a vacuum. It was precisely these observations, however, as continued by Lenard and others, which presently made it necessary to see in electricity nothing else than a special manifestation of inert mass.
The developments leading up to this stage are recent and familiar enough to be briefly summarized. The first step was once more an accident, when Röntgen (or rather one of his assistants) noticed that a bunch of keys, laid down by chance on top of an unopened box of photographic plates near a cathode tube, had produced an inexplicable shadow-image of itself on one of the plates. The cathode tube was apparently giving off some hitherto unknown type of radiation, capable of penetrating opaque substances. Röntgen was an experimentalist, not a theorist; his pupils used to say privately that in publishing this discovery of X-rays he attempted a theoretical explanation for the first and only time in his life - and got it wrong!
However, this accidental discovery had far-reaching consequences. It drew attention to the fluorescence of minerals placed in the cathode tube; this inspired Becquerel to inquire whether naturally fluorescent substances gave off anything like X-rays, and eventually - yet again by accident - he came upon certain uranium compounds. These were found to give off a radiation similar to X-rays, and to give it off naturally and all the time. Soon afterwards the Curies succeeded in isolating the element, radium, an element which was found to be undergoing a continuous natural disintegration. The way was now clear for that long series of experiments on atomic disintegration which led finally to the splitting of the nucleus and the construction of the atomic bomb.
*
A typical modern paradox emerges from these results. By restricting his cognitive powers to a field of experience in which the concept of force as an objective reality was unthinkable, man has been led on a line of practical investigation the pursuit of which was bound to land him amongst the force-activities of the cosmos. For what distinguishes electric and sub-electric activities from all other forces of physical nature so far known to science, is that for their operation they have no need of the resistance offered by space-bound material bodies; they represent a world of pure dynamics into which spatial limitations do not enter.
Equally paradoxical is the situation of theoretical thinking in face of that realm of natural being which practical research has lately entered. We have seen that this thinking, by virtue of the consciousness on which it is founded, is impelled always to clothe its ideas in spatial form. Wherever anything in the pure spatial adjacency of physical things remains inexplicable, resort is had to hypothetical pictures whose content consists once more of nothing but spatially extended and spatially adjacent items. In this way matter came to be seen as consisting of molecules, molecules of atoms, and atoms of electrons, protons, neutrons, and so forth.
In so far as scientific thought has held to purely spatial conceptions, it has been obliged to concentrate on ever smaller and smaller spatial sizes, so that the spatially conceived atom-picture has finally to reckon with dimensions wherein the old concept of space loses validity. When once thinking had started in this direction, it was electricity which once more gave it the strongest impulse to go even further along the same lines.
Where we have arrived along this path is brought out in a passage in Eddington'sThe Nature of the Physical World.There, after describing the modern picture of electrons dancing round the atomic nucleus, he says: 'This spectacle is so fascinating that we have perhaps forgotten that there was a time when we wanted to be told what an electron is. This question was never answered. No familiar conceptions can be woven round the electron; it belongs to the waiting list.' The only thing we can say about the electron, if we are not to deceive ourselves, Eddington concludes, is: 'Something unknown is doing we don't know what.'4
Let us add a further detail from this picture of the atom, as given in Eddington'sPhilosophy of Physical Science.Referring to the so-called positron, the positive particle regarded as the polar opposite of the negative electron, he remarks: 'A positron is a hole from which an electron has been removed; it is a bung-hole which would be evened up with its surroundings if an electron were inserted. ... You will see that the physicist allows himself even greater liberty than the sculptor. The sculptor removes material to obtain the form he desires. The physicist goes further and adds material if necessary - an operation which he describes as removing negative material. He fills up a bung-hole, saying he is removing a positron.' Eddington thus shows to what paradoxical ideas the scientist is driven, when with his accustomed forms of thought he ventures into regions where the conditions necessary for such forms no longer exist; and he concludes his remarks with the following caution: 'Once again I would remind you that objective truth is not the point at issue.'
By this reminder Eddington shows how far science has reconciled itself to the philosophic scepticism at which man's thinking had arrived in the days of Hume. In so far as the above remark was intended to be a consolation for the bewildered student, it is poor comfort in the light of the actions which science has let loose with the help of those unknown entities. For it is just this resignation of human thought which renders it unable to cope with the flood of phenomena springing from the sub-material realm of nature, and has allowed scientific research to outrun scientific understanding.
1E. du Bois-Raymond:Investigations into Animal Electricity(1884). Galvani published his discovery when the French Revolution had reached its zenith and Napoleon was climbing to power.
2The above account follows A. J. von Oettingen's edition of Galvani's monograph,De viribus electricitatis in motu musculari.
3For what follows seeThe Life of Sir William Crookes,by E. E. Fournier D'Albe (London, 1923).
4Eddington's italics. See also, in this respect, Professor White head's criticism of the hypothetical picture of the electron and its behaviour.